On Mon, 25 Mar 2024, Thomas Cameron wrote:
Fedora can install on either legacy BIOS mode or modern UEFI. But when it installs on UEFI systems, it creates a special partition mounted on /boot/efi. If you boot a system which was installed in BIOS mode in UEFI mode, it doesn't see that partition and won't boot.
To be clear: I wasn't trying to boot the hard drive or install to it. I was just trying to boot the DVD. Eventually I succeeded by disabling UEFI. The need surprised me. To boot from the hard drive, I had to re-enable UEFI.
If you want to run Fedora in UEFI mode, I am relatively certain you have to reinstall (but I could absolutely be wrong). When I got a machine which supported UEFI, I initially turned off UEFI and Secure Boot because I'd heard horror stories about them with Linux. When I changed it to UEFI, I couldn't access my Linux installation. But since I had a backup of my home directory on another machine, I just nuked it and reinstalled, then restored my home directory.